text: # -*- coding: utf-8 -*-
  
  from numpy import pi, arcsin
  
  
  def comp_angle_opening(self):
      """Compute the average opening angle of the Slot
  
      Parameters
      ----------
      self : SlotW61
          A SlotW61 object
  
      Returns
      -------
      alpha: float
          Average opening angle of the slot [rad]
  
      """
  
      slot_pitch = 2 * pi / self.Zs
      tooth_angle = float(2 * arcsin(self.W0 / (2 * self.get_Rbo())))
  
      return slot_pitch - tooth_angle
  